THE GYMXOSPERMAE : CYCADALES, ETC. 



771 



Sclerenchyma 



Palisade cells 



Fig. 771. — Weiuitschia inirabiUs. A portion of a trans- 

 verse section of a leaf showing the sunken stomata 

 and alternating bands of sclerenchyma and palisade 

 cells. 



The Inflorescences. 



The branched inflorescences arise from oval depressions in the surface 

 of the ridges, normally from the ridge above the leaf base, though the lower 

 one also sometimes bears them. They are formed regularly every year and 

 drop off after functioning, leaving a row of scars on the ridge. Each ridge 

 apparently remains fertile for several years before being replaced by another, 

 as described above. 



Each inflorescence axis contains two irregular rings of vascular bundles, 

 from the inner of which are supplied the bracts and branches. Below each 

 node the bundles form irregular, convoluted groups, some with inverted 

 orientation, which recalls the structure of the stem in certain fossil 

 Medullosae. 



The male axes branch dichasially two or three times, each pair of branches 

 being subtended by a pair of connate bracts. The ultimate branches are the 

 strobili, which are sessile and arranged in groups of three, a middle, terminal 

 one with one at each side, each group being also subtended at the base by a 

 pair of connate bracts. The strobili are bright red when ripe and form a 

 striking contrast to their green stalks (Fig. 772). 



The Male Strobilus. 



Each male strobilus is about 2 to 3 cm. long and rather slender. On its 

 central axis are borne four rows of closely overlapping bracts, in decussate, 

 connate pairs, the whole arrangement being geometrically regular (Fig. 773). 

 In the axil of each bract, except a few basal ones, stands a single flower 



